Supreme Court revises rules on expert and lay witnesses

May 29, 2003

The Mississippi Supreme Court on Thursday amended rules that govern admissibility of expert witness and lay witness opinion testimony.

The rules apply to the admissibility of scientific evidence opinion testimony as well as other technical or specialty fields.

Supreme Court Chief Justice Edwin L. Pittman said, "We've got all sorts of weird science now." Before testimony is admissible, "there's got to be some body of science that supports that," Pittman said.

The Supreme Court adopted changes in Rules 701 and 702 of the Mississippi Rules of Evidence. The Supreme Court in written comments about Rule 702 said, "By the 2003 amendment of Rule 702, the Supreme Court clearly recognizes the gate keeping responsibility of the trial court to determine whether the expert testimony is relevant and reliable."

The court in written comments explained that the change tracks amendments made to the Federal Rules of Evidence in 2000. The federal rule uses the test established in the 1993 U.S. Supreme Court decision in the case of Daubert v. Merrell Dow Pharmaceuticals, Inc., reported as 509 U.S. 579.

Before the revisions, Rule 702 of the Mississippi Rules of Evidence already included language that permitted expert witness opinion testimony "if scientific, technical or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue...."

New language in the revision sets additional standards for accepting expert witness opinion testimony. The rule says the expert opinion testimony may be admissible if:

(1) the testimony is based upon sufficient facts or data;

(2) the testimony is the product of reliable principles and methods, and;

(3) the witness has applied the principles and methods reliably to the facts of the case.

Pittman said, "This strengthens the hand of the trial judge to decide what goes in or doesn't go in."

The Supreme Court in its revision to Rule 701 regarding lay witness opinion testimony added language that further defines lay testimony as "not based on scientific, technical, or other specialized knowledge within the scope of rule 702."

In written commentary, the court said, "The 2003 amendment to Rule 701 makes it clear that the provision for lay opinion is not an avenue for admission of testimony based on scientific, technical or specialized knowledge which must be admitted only under the strictures of Rule 702."

A copy of the rule changes is available on the Supreme Court's web site,